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Low-Vibration Tracks (LVTs) are widely used in subway tunnels for their excellent performance, but the application in heavy-duty railways still requires a lot of feasibility studies. In this study, the statics performance of LVT under different axle loads, load direction, and load position is explored using the finite element software Abaqus. The Timoshenk beam element and nonlinear spring element 3D solid element are used to represent rails, fasteners, and the other track structure respectively. The paper established the finite element model of LVT to study the mechanical characteristics of low vibration track structure under varying loading condition. The applied loads are determined according to the Heavy-Haul Railway Track Structure Design Code. The results shows: (1) The deformation and stress of the LVT structure show a linear relationship with the increase of the axle load. (2) Slab end loading and lateral load are more unfavorable to the stress and deformation of the track structure. When slab end is loaded with vertical load, the vertical load is distributed on four supporting blocks along the longitudinal direction with a ratio of 1:4:4:1, and the lateral direction is mainly borne by two adjacent fastener nodes with the total load proportion of 47% and 47% respectively. (3) The LVT structure can guarantee the safety of static performance under 30 t axle load and the maximum axle load should not exceed 36 t. The paper provides a guideline for the construction and maintenance of LVT structure in heavy haul railway.

This paper uses the long-span steel truss slab track as its research subject to analyze the new type of sleeper slab track structure with an experimental method. Firstly, a full-scale model was established in the laboratory to form a “rail–sleeper slab–self-compacting concrete cushion–steel beam” composite structure, and a fatigue test was performed on the track structure. The cyclic load was set up as a sine form with a range between 75 and 375 kN at a 5 Hz interval and 3 × 106 cycles. Based on the test, the performance of the track structure under cyclic train load was studied. Secondly, after every 106 loading cycles, the vertical static loading test and horizontal resistance test of the track structure were carried out to obtain the strain and displacement under different loading cycles. Finally, after 3 × 106 cycles of sine cyclic loading, the horizontal ultimate resistance test of the track structure was carried out to study its horizontal failure mode. The aims of this paper were to verify the applicability of the sleeper slab track, identify the mechanical properties, and determine the unfavorable position. The findings can provide an important reference for the practical use of the sleeper slab track structure.

The key functions of the fastener system are to hold the rail against the sleepers and to restrain the rail from all forms of movements that could lead to loss of geometry and stability of the track. Thus, fastener resistance is an important parameter in the continuously welded rail technology. This study investigates the characteristics of the longitudinal resistance of WJ-8 fasteners subjected to varying torques and vertical loadings. The vertical loading was applied to the rail section through a reaction frame, while the torque was applied using a digital torque wrench. Two types of fasteners, conventional-resistance and small-resistance fasteners, were tested in this study. The study shows that: (1) The growth rate of the longitudinal resistance of the fastener is independent of the vertical loading until the fastener slips. (2) The slip resistance of fasteners increases as the torque and vertical loading are increased. (3) The relationship between the longitudinal resistance and the displacement of fasteners at varying torques and vertical loadings fits a power index function. (4) The relationship between the longitudinal resistance and the displacement of the fastener exhibits hysteresis. The study serves as a reference for verifying and improving future calculation methods for the longitudinal resistance of fasteners in continuously welded rails.

The rails at the transition between a bridge or subgrade and a tunnel tend to creep longitudinally because of a temperature gradient on the rail, which can cause irregularity in the track. The longitudinal temperature distribution along the rail and the longitudinal resistance of the fasteners are the main influences on rail creep. In this paper, the linear and nonlinear models of longitudinal temperature distribution on rails and the longitudinal resistance of fasteners are tested for their accuracy in predicting rail creep. By researching the rail at the temperature-transition zone, differential equations for the longitudinal displacement and force of the rail are established. To predict the changes that a rail will experience in a temperature-transition zone, expressions for the longitudinal displacement and force are derived from these differential equations. The derived calculation scheme is tested for three conditions: linear models of both rail temperature and longitudinal resistance, linear rail temperature and nonlinear resistance, and nonlinear models of both rail temperature and displacement. The maximum longitudinal rail displacement and the maximum longitudinal additional force in all three conditions are compared to reveal the influence of the maximum temperature force gradient multiple and the maximum fastener resistance on longitudinal displacement.

The aim of the research is the design of prefabricated steel-spring floating-slab track to be applied in urban express rail transit systems. Using a developed vehicle-track dynamic-coupling equation for steel-spring floating-slab track, the effects of length, thickness, vertical damping, and use of side-mounted isolators on the floating-slab track were investigated experimentally using full-scale model and under different working conditions. The finding of the study revealed the following: (1) The prefabricated steel-spring floating-slab track can be applied to urban express rail transit, because it meets the requirements of high-speed transit while efficiently reducing noise. (2) The floating-slab track’s stability slightly increases with the increase of its length and thickness. As thickness increases, vertical displacement of the rail increases slightly, and lateral stability increases, thereby slightly improving the vehicle’s running stability. (3) When the intercity electric multiple-unit train travels along the prefabricated steel-spring floating-slab-track bed at different speeds, the wheel-axle lateral force, wheel-rail vertical force, the derailment coefficient, the wheel-weight reduction rate, and the lateral acceleration of the vehicle body are all less than the specified limits of Chinese code, thus fully meeting the safety requirements of train operation. (4) Appropriately increasing the vertical-support damping of the floating slab can improve the vehicle’s vertical dynamic performance, reduce the vertical displacement of the rail, and lower the vibration response of the floating slab. (5) Adding side-mounted vibration isolators at the joint of the floating slab could greatly improve the stability of the floating slab itself and appropriately reduce the vehicle’s vertical vibration response. Due to the optimization and establishment of relevant factors influencing the performance of prefabricated steel-string floating-slab track achieved in the study, the results obtained are particularly useful for setting safety, comfort, and stability requirements of the floating slab.

van der Waals heterojunctions (vdWHs) formed between 2D materials have attracted tremendous attention recently due to their extraordinary properties, which cannot be offered by their individual components or other heterojunctions. Intriguing electronic coupling, lowered energy barrier, intimate charge transfer, and efficient exciton separation occurring at the atomically sharp interface promise their applications in catalysis, which, however, are largely unexplored. Herein, we demonstrate a 0D/2D vdWH between 0D graphene quantum dots (GQDs) and 2D pristine graphene sheets, simply prepared by ultrasonication of graphite powder using GQDs as intercalation surfactant. Such an all-carbon Schottky-diode-like 0D/2D vdWH is employed for the emerging photoelectrochemical catalysis (water splitting) with high performance. The demonstrated low-cost and scalable bottom-up growth of heteroatom-doped GQDs will greatly promote their widespread applications. Moreover, the mechanisms underlying GQD growth and heterojunction-mediated catalysis are revealed both experimentally and theoretically. Accepted version

Under long-term temperature loading, long bridges stretch and deform, causing the beam and rail to move relative to each other. This phenomenon could cause a gradual slide of the rail relative to the fastener composite pad and ultimately results in the slipping out of the fastener pad at the end of the ballastless track bridge changes. The slipping out of the fastener composite pad changes the longitudinal resistance of the fastener and causes shock of the train on the rail structure due to direct contact between the rail and the tie, thus inhibiting the normal use of the line. In this paper, a reciprocating tensile test was carried out on a WJ-8 small resistance fastener to explore the breaking process of the fastener composite pad, identify the interaction mechanism of the fastener composite pad under the rail, and ultimately determine the influence of the pad on the longitudinal resistance of the fastener. The results show that the two factors that affect the longitudinal resistance of the fastener under reciprocating loading are the surface roughness and displacement of the fastener composite pad. While the surface roughness of the fastener composite pad is the main influencing factor in the early stage, the displacement of the composite pad has a greater impact on the later stage. The research results of this paper can provide an important reference for the maintenance and repair of ballastless track fasteners on bridges.

A full-Stokes polarization imaging method based on the self-organized grating array was presented. By focusing the ultra-fast laser with moderate fluence into fused silica, the self-organized grating array was fabricated, featuring the optical properties similar to wave plates. A set of four independent polarization measurements were simultaneously acquired with designed grating array mounted in the focal plane of an imaging detector. Experimental results including the device fabrication, calibration and optimization were presented. Finally, a principle verification experiment was implemented for our polarization imaging method.

Tunable and efficacious modulation of photo-induced charge carrier separation and transfer in photoelectrochemical (PEC) cell for solar water splitting constitute a central challenge. Herein, high-efficiency plasmon-induced hot carriers transfer channel has been rationally and progressively constructed by judicious layer-by-layer assembly of graphene quantum dots (GQDs) and plasmonic metal nanocrystals (Ag NCs) on the one-dimensional semiconductor (TiO2 nanorods arrays, TiO2 NRs) framework, resulting in a well-defined spatially multilayered photoanode. The unique and alternate integration of GQDs with Ag NCs on the TiO2 NRs is closely associated with charge transfer behaviors. It was unveiled that Ag NCs in situ integrated in the multilayered film enable hot electron generation, and simultaneously play a crucial role in finely relaying electron transfer from GQDs to TiO2. This gives rise to significantly enhanced solar-powered PEC water splitting performances of TiO2 NRs@Ag@GQDs ternary multilayered heterostructure, which far surpasses the corresponding binary and single counterparts. Consequently, intrinsic correlation of metal NCs with GQDs in terms of charge transport was for the first time clarified.

With the gradual increase of the cargo weight of heavy-haul trains, the traditional ballasted track with the accumulation of stone and ballast has been unable to meet its structural safety requirements. From the comparison of the three common ballastless tracks in China, it can be seen that the low-vibration track (LVT) has the advantages of reasonable structure, low cost, and easy maintenance. Therefore, the design and research of heavy-haul railways are focused on, and it is urgent to study the applicability of LVT in heavy-haul railways. Method: By improving the slope of the short side of the LVT support block, the support block has a better load bearing capacity, so as to achieve the purpose of bearing a larger axle load. Through 1:1 full-scale model test and finite element simulation, the static mechanical properties of Improved LVT (ILVT) and Traditional LVT (TLVT) are compared and analyzed. Result: Compared with TLVT, ILVT has smaller vertical displacement and track gauge changes when subjected to the same load. The proven and reliable finite element model also shows that ILVT’s load sharing is less affected. In the case of achieving the same deformation, ILVT can withstand greater vertical and lateral loads. Conclusions: Compared with the TLVT, the ILVT design can reduce the vertical displacement of the rail and the supporting block, better control the track subsidence, and improve the driving safety of the LVT. At the same time, ILVT improves the anti-overturning ability of the rail and support block under lateral load, reduces the expansion of the gauge and the lateral spacing of the support block, and improves the stability of the track structure. ILVT can also be considered for the weight of 40t and other large axle load, and has broad application prospects.

To further explore the fatigue characteristics of the CRTS (China Railway Track System) type III slab ballastless track structure generally used for high-speed railways, the fatigue damage of CRTS III type slab ballastless track structure system under the action of heavy-haul trains was studied. Based on the three-stage model, the CRTS III slab ballastless track structural system fatigue finite element numerical model was established, with particular emphasis on the fatigue characteristics of the self-compacting concrete of the CRTS III slab ballastless track under a load of heavy haul trains. To verify the reliability of the established model, the track structure displacement and stress under static load and fatigue load were analyzed and compared. The results shows that the model can be used to explore the fatigue damage law of the structural system of the CRTS III slab ballastless track under the action of heavy-haul trains. The results of further analysis showed that: (1) For self-compacting concrete, the maximum longitudinal tensile stress is greater than the maximum lateral tensile stress (2) For the longitudinal direction of the lower surface of the self-compacting concrete, once the tensile stress reaches the tensile strength of concrete, the self-compacting concrete cracks; as the number of fatigue loads further increases, more cracks will develop from the sides of the slab centre in the self-compacting concrete (3) The larger the axle load, the higher the stress level of each layer of the track structure, the faster the concrete damage rate, and the earlier the concrete cracks. As axle load is greater than 35 t, the damage of self-compacting concrete is more pronounced.

A meshless formulation for fracture analysis of stiffened plates is introduced in this paper. Based on an improved meshless model of stiffened plates proposed by the authors, in which flat plate and ribs are combined by implementing the displacement compatibility conditions between them, a crack is introduced by the diffraction method. The expanded basis function and the weight function based on t−1 distribution are employed. Inheriting the meshless advantages from the model, the ribs in our formulation can be set at any location on the flat plate, and the remeshing of the flat plate is naturally avoided when rib location changes. Some numerical examples are investigated by the proposed formulation and the commercial FEM software ANSYS, and the accuracy of the proposed formulation is verified. The effects of ribs on the displacement, stress and SIFs of the stiffened plates that have cracks are discussed.

The broad applicability of super-resolution microscopy has been widely demonstrated in various areas and disciplines. The optimization and improvement of algorithms used in super-resolution microscopy are of great importance for achieving optimal quality of super-resolution imaging. In this review, we comprehensively discuss the computational methods in different types of super-resolution microscopy, including deconvolution microscopy, polarization-based super-resolution microscopy, structured illumination microscopy, image scanning microscopy, super-resolution optical fluctuation imaging microscopy, single-molecule localization microscopy, Bayesian super-resolution microscopy, stimulated emission depletion microscopy, and translation microscopy. The development of novel computational methods would greatly benefit super-resolution microscopy and lead to better resolution, improved accuracy, and faster image processing.

Real telephony speech recognition task is challenging due to 1) diversified channel distortions and 2) limited access to the real data because of the data privacy consideration. In this paper, assuming no real telephony data are available, we employ diversified audio codecs simulation based data augmentation method to train telephony speech recognition system. Specifically, we assume only wide-band 16 kHz data are available, and we first down-sample the 16 kHz data to the 8 kHz data; we then pass the down-sampled data through various categories of audio codecs to simulate the real channel distortion. As a result, we train our speech recognition with such distorted data. To analyze the effectiveness of different audio codec simulation methods, we classify them into three main categories according to their distortion severity, in terms of their spectrogram analysis. We conduct experiments on various real telephony test sets to show the effectiveness of the proposed data augmentation method. The result shows that the real data is more close with highly distorted simulation data, since the model with highly distorted data reduce the Word-Error-Rate 7.28%–12.78% compared to the baseline.

Heavy-haul railway has been developed rapidly in many countries in the world due to its great social and economic benefits. One of the key technologies for heavy-haul railway is the reduction of vibration on the track structures and its surrounding due to impact load induced by the train in service. The vibration behaviors of two kinds of low-vibration track (LVT) systems for heavy-haul railway are investigated in this paper. Firstly, two indoor full-scale low-vibration track models (new LVT and traditional LVT), which include rail, fastener, bearing block, rubber boot, track slab, and foundation base, were constructed according to design drawings. Secondly, the vibration responses of the different track components under the impact excitation of a dropping wheelset were measured. Thirdly, the time-domain characteristics of each track component of the two LVTs were compared by the acquired vibration time-history curves. Finally, the frequency-domain distribution was analyzed, and the vibration reduction performance was evaluated by the comprehensive time-frequency analysis results. The results show the new LVT has lower vibration acceleration, shorter duration of vibration period, lower vibration frequency of track components, and most importantly an obvious vibration reduction effect on the ground. The research results are useful to further optimize the design of LVT to reduce the vibration under train impact load.

Medium damping fasteners have the advantages of low cost, easy maintenance, and convenient in gauge adjustment, etc., which are gradually and widely used in metro construction. In order to study the performance of medium damping fasteners in a driving environment, we performed measurement on site about the vertical and lateral displacement of the rail, as well as the vertical acceleration of the rail and the tunnel wall on a straight and curved metro cross-section with medium damping fasteners. By comparing with the results of ordinary fasteners, it can be seen that: (1) The medium damping fastener has a vibration reduction effect on the vertical acceleration level of the tunnel wall in the frequency range of 6.3∼31.5Hz and 50∼80Hz; moreover, it has a vibration reduction effect on the lateral acceleration of the tunnel wall in the frequency range of 5∼31.5 Hz and 50∼80 Hz. (2) The vertical and lateral displacement of the rail and the gauge change with the medium damping fasteners are larger than those of the ordinary fasteners. (3) The maximum Z vibration level measured from the tunnel wall is most suitable for evaluating the source strength of the metro, wherein the source strength of this metro line is 88.42 dB.

To study subway turnouts’ adaptability to steep gradients, a finite element model of a metro No. 9 simple turnout was established. The main works include: (1) The train’s most unfavourable loading condition was modelled. (2) The turnout’s longitudinal displacement and stress were analysed with different gradients under the train braking load, temperature change load and a combination of the two, to determine the structure’s safety and stability under the most unfavourable working conditions. (3) The turnout structure’s cumulative longitudinal deformation under reciprocating load was studied. Both a fastener longitudinal resistance-displacement experiment under reciprocating load and a numerical simulation of No. 9 turnout modelled by the finite element modelling software, ANSYS, were carried out to study the gradient’s influence on the turnout’s longitudinal mechanical characteristics. (1) The turnout’s longitudinal displacement and stress increase linearly with an increase in gradient and temperature change, both of which are unfavourable to the turnout structure. As the gradient increases from 0‰ to 30‰, the longitudinal stress and displacement increase by more than 10%. (2) The turnout’s rail strength and displacement on a 30‰ slope under the most unfavourable load conditions are within the specification limitations. (3) Under reciprocating load, the fastener longitudinal stiffness decreases and the maximum and residual longitudinal displacement of the switch rail increase; an increased gradient intensifies these effects on the turnout.

In this paper, relying on the National Engineering Laboratory of High-Speed Railway Construction Technology, a full-scale model of the double-block ballastless track structure is established, and the strain analysis of the layered track structure under different static loads is carried out, which has a certain practical significance for the design and maintenance of the high-speed railway ballastless track in our country. Research conclusion: (1) Under the action of static load, the sleeper directly under the rail is under compression; the four corners of the sleeper are tensile strain; (2) The strain at each measuring point on the surface of the track slab around the sleeper is compressive strain; the edge of the top surface of the track slab is compressive strain; The longitudinal strain at the bottom of the side of the track slab is tensile strain; (3) Under static load, the longitudinal strain measurement point on the top surface of the base plate is tensile strain at a distance of two sleepers from the static load position; the longitudinal strain at the bottom of the side of the base plate is tensile strain.

The train sometimes needs to brake frequently on the turnout, although the braking force does not exceed the limit resistance of fastener, cumulative displacement of rail occurs because of the long-term effect of the train brakes, thus, the relationship between the cumulative displacement of rail and the number of train braking actions should be explored. Aiming at the spring bar type III fastener, a 1:1 physical indoor simulation test was carried out, and an electromagnetic relay device was used to simulate the train load, force, and displacement sensors for data collection. Then a single load no more than the maximum resistance of fastener was applied to the rail end to explore the relationship between the number of loads and the rail cumulative deformation. The rail longitudinal cumulative displacement changes linearly in positive correlation with the number of load actions, and increases faster when the number of load actions is small. As the number of repeated loads increases, the above-mentioned relationship approximately and credibly obeys the power function distribution. Repeatedly applying load no more than the maximum longitudinal resistance of fastener to the rail, the existence of the rail cumulative displacement caused by frequent train braking can be demonstrated, and the relationship curve between the rail displacement and the number of loads can be obtained. Applying the fitting formula, the rail displacement after a specific number of loading times can be attained, and then referring to specific codes, we can determine whether it will exceed the safety limit.

The reliability connection of the plastic dowel and the bolt largely determines the normal function of the railway fastener system. However, the failure of the dowel and the uplift of the bolt are found during railway operation. Therefore, a series of pull-out and pre-tightening force tests for plastic dowel of the railway sleeper are carried out. Not only the relationship between the bolt ultimate pull-out capacity and the effective anchorage length is obtained, but the failure pattern of the plastic dowel is analysed. In addition, the relationship between pre-tightening force and installing torque, and the influence of freeze-thaw cycles on pre-tightening force are investigated. The above relationships could be described by linear equations, the failure of the dowel during pull-out test is dominated by bending failure pattern and the freeze-thaw cycles for the space between the bolt and the dowel with full of water (9 mL) could cause reduction of the pre-tightening force.

To investigate the clinical and genetic risk factors associated with hepatocellular carcinoma (HCC) in cirrhotic patients with chronic hepatitis B (CHB).Nine hundred forty-nine Chinese Han patients with CHB were studied, including noncirrhotic patients without HCC (N = 234), cirrhotic patients without (N = 281) and with HCC (N = 434). Patients were genotyped for 10 candidate single nucleotide polymorphisms (SNPs) by the polymerase chain reaction (PCR)-ligase detection reaction (LDR) method.By multivariate logistic regression analysis adjusted for Child-Pugh scores, noneffective antiviral treatment, drinking history, family history of HCC, and age ≥50 years old were associated with HCC risk (odds ratio [OR] = 5.923, 2.456, 2.241, 1.955, respectively). Sixty-two of 170 cirrhotic patients who achieved sustained virological suppression by antiviral treatment developed HCC, with fatty liver disease, family history of HCC, and family history of hepatitis B virus (HBV) infection as the risk factors (OR = 11.646, 3.339, 2.537, respectively). The SNPs associated with HCC risk in patients with cirrhosis and CHB were rs11536889 in TLR4 and rs2853744 in SPP1. Polymorphisms of TLR4 rs2149356, AP3S2 rs2290351, STXBP5L rs2169302, MLEC rs7976497, and SOCS3 rs4969168 were associated with HCC risk in specific stratified analyses with gender, age, and drinking history in the cirrhotic patients.Inadequate antiviral treatment, family history of HCC, drinking history, and age ≥50 years old are risk factors for HCC. Sustained suppression of HBV does not eliminate the risk of HCC. Specific host genetic factors may impact HCC development in Han Chinese cirrhotic patients with CHB, including SNPs in TLR4, SPP1, AP3S2, STXBP5L, MLEC, and SOCS3, which warrant further validation in additional cohorts.

Three-dimensional optical super-resolution imaging is capable of providing 3D visualization of cellular structures in nanoscale detail. The past decade has witnessed the blossoming of 3D super-resolution imaging technologies. In this review, we comprehensively discuss and compare the imaging depth, resolution enhancement, and imaging speed of the existing 3D super-resolution imaging techniques.

Due to the limited electronic conductivity, the application of many metal oxides that may have attractive (photo)-electrochemical properties has been limited. Regarding these issues, incorporating low-dimensional conducting scaffolds into the electrodes or supporting the metal oxides onto the conducting networks are common approaches. However, some key electronic processes like interfacial charge transfer are far from being consciously concerned. Here we use a carbon-TiO2 contact as a model system to demonstrate the electronic processes occurring at the metal-semiconductor interface. To minimize the energy dissipation for fast transfer of electrons from semiconductor to carbon scaffolds, facilitating electron tunneling while avoiding high energy-consuming thermionic emission is desired, according to our theoretical simulation of the voltammetric behaviors. To validate this, we manage to sandwich ultrathin TiO2 interlayers with heavy electronic doping between the carbon conductors and dopant-free TiO2. The radially graded distribution of the electronic doping along the cross-sectional direction of carbon conductor realized by immobilizing the dopant species on the carbon surface can minimize the energy consumption for contacts to both the carbon and the dopant-free TiO2. Our strategy provides an important requirement for metal oxide electrode design.

A layer-by-layer (LbL) assembly of highly ordered nitrogen-doped graphene quantum dots (N-GQDs)/ZnO nanowire (NW) heterostructures was demonstrated as a high performance photoanode in photoelectrochemical (PEC) hydrogen generation for the first time. The nitrogen doping of GQDs was achieved by a facile synthesis strategy under ambient conditions, based on which N-GQDs were uniformly and intimately deposited on the ZnO NW framework via pronounced electrostatic interaction. The deposited amount of N-GQDs and PEC water splitting performances of N-GQDs/one-dimensional (1D) semiconductor heterostructures can be tuned by the assembly layer. The integrative roles of nitrogen doping and photosensitization of GQDs in conjunction with intimate interfacial integration between the photoanode components afforded by the LbL assembly strategy were found to collaboratively contribute to enhanced PEC water splitting. It is anticipated that our work could afford a facile and general strategy for steering toward the rational design of a large variety of N-GQDs/1D semiconductor nanoarchitectures for extensive photocatalytic or PEC applications.

Background and Purpose The orphan nuclear receptor Nur77 is implicated in the survival and apoptosis of cancer cells. The purpose of this study was to determine whether and how Nur77 serves to mediate the effect of the inflammatory cytokine TNF-α in cancer cells and to identify and characterize new agents targeting Nur77 for cancer therapy. Experimental Approach The effects of TNF-α on the expression and function of Nur77 were studied using in vitro and in vivo models. Nur77 expression was evaluated in tumour tissues from breast cancer patients. The anticancer effects of honokiol and its mechanism of action were assessed by in vitro, cell-based and animal studies. Key Results TNF-α rapidly and potently induced the expression of Nur77 in breast cancer cells through activation of IκB kinase and JNK. Knocking down Nur77 resulted in TNF-α-dependent apoptosis, while ectopic Nur77 expression in MCF-7 cells promoted their growth in animals. Levels of Nur77 were higher in tumour tissues than the corresponding tissues surrounding the tumour in about 50% breast cancer patients studied. Our in vitro and animal studies also identified honokiol as an effective sensitizer of TNF-α-induced apoptosis by inhibiting TNF-α-induced Nur77 mRNA expression, which could be attributed to its interference of TNFR1's interaction with receptor-interacting protein 1 (RIPK1). Conclusions and Implications TNF-α-induced Nur77 serves as a survival factor to attenuate the death effect of TNF-α in cancer cells. With its proven human safety profile, honokiol represents a promising agent that warrants further clinical development.

Impact loads from trains in operation induce vibration on track structure and its surroundings, which causes track deterioration and negative environmental effects over time. In this study, the vibration reduction characteristics of the ballasted track with rubber composite sleeper were measured and compared to that of the ballasted track with concrete sleeper using full-scale in-door laboratory models. The sleepers were subjected to impact excitations through a free-falling hammer weight and the vibration responses of the track components were analysed in both time and frequency-domains. The results show that; 1. The peak acceleration and root-mean-square (RMS) distribution on the ballasted track with rubber composite sleeper are lower than that of the ballasted track with concrete sleeper. This implies better vibration attenuation capacity. 2. The time-domain analysis showed that the track with rubber composite sleeper has lower vibration acceleration energy, reduced velocity and shorter vibration duration. 3. When compared to ballasted track with concrete sleeper, the track with rubber composite sleeper reduced the overall vibration levels of the ballasted track by 1.11 dB, −2.32 dB and 1.69 dB for the sleepers, ballast and ground respectively. Consequently, the ballasted track with rubber composite sleeper has significant vibration reduction effect on the ground.

At present, rail transit is developing rapidly in the world, and this means new and changing requirements for the training of talents in railway engineering experiments. Given the current problems of limited laboratory/field instruments for railway engineering experimentsand the safety/administrative difficulties of going to the frontline of railway lines to teach railway engineering experiemnts in the field, the Department of Railway Engineering of Central South University tried to introduce virtual reality (VR) technology to teach students experiments in the field of railway engineering. Through the virtualized experimental methods, students can carry out railway engineering experiments such as; vehicle wheel pair off-axis experiments, track geometry and position detection, etc by immersive means. It was observed that after performing virtual simulation experiments, students appeared conversant in subsequent field experiments. Thus, VR greatly improves the teaching efficiency of railway engineering experiments.

Fluorescence fluctuation-based superresolution techniques can achieve fast superresolution imaging on a cost-effective wide-field platform at a low light level with reduced phototoxicity. However, the current methods exhibit certain imaging deficiencies that misinterpret nanoscale features reconstructed from fluctuating image sequences, thus degrading the superresolution imaging quality and performance. Here we propose cross-cumulant enhanced radiality nanoscopy (CERN), which employs cross-cumulant analysis in tandem with radiality processing. We demonstrated that CERN can significantly improve the spatial resolution at a low light level while eliminating the misinterpretations of nanoscale features of the existing fluctuation-based superresolution methods. In the experiment, we further verified the superior performance of CERN over the current methods through performing multicolor superresolution imaging of subcellular microtubule networks and clathrin-coated pits as well as the high-precision reconstruction of densely packed RNA transcripts.

Single wavelength laser sources used for pumping lasers demonstrate poor resistance to environmental factors. Therefore, a method for employing an amplified spontaneous emission (ASE) light source for pumping thulium ion (Tm 3 + ) doped silica microsphere (TDSM) lasers is proposed. The ASE source emits non-polarized light with a broad bandwidth. When using ASE light, there is always a wavelength group that resonates with the high-Q microsphere to adaptively couple into TDSM and excite the Tm 3 + ion. The ASE source resists the resonance wavelength mismatch owing to the variation of pump light polarization caused by vibration and the variation induced by temperature change. With ASE light pumping, we demonstrated the generation of 2 μ m whispering gallery modes (WGMs) laser with a very low threshold.

In this paper, a full-scale model of Low Vibration Track was established and three working conditions were applied to a single bearing block; these include: vertical load at the end of the track slab, combination of horizontal and vertical load at the end of the track slab, and vertical load at the middle of the track slab. By applying four times static wheel load to the full-scale model, the relationship between the stress of the track structure and the load under different working conditions was investigated. The corresponding load values were obtained when the track slab and the bearing block reached the axial tensile strength of the concrete. Through the static load test, the weak position of the track structure was found, and the development trend of the crack was obtained. (1) Obtained the maximum stress of the concrete of the track slab at the corner of the bearing block, the maximal stress of the concrete of the track slab, the stress at the bottom of the bearing block, and the stress at the bottom of the bearing block under different working conditions. (2) The horizontal load of the train increased the force of the track slab concrete at the corners of the bearing block. (3) Compared the strain of different location of the track slab and different working conditions. (4) Observed the positions of slight crack and its development trend appeared on track slabs in different working conditions. (5) For the weak part of the track structure, it can be improved by measures such as increasing the thickness of the end of the track slab and arranging stirrups in the track slab around the support block. The research results provide reference for the design, application and maintenance of Low Vibration Track in the heavy-haul railway tunnel.

In this paper, we propose a promising super-resolution imaging scheme in fluorescence lifetime domain (lifetime super-resolution optical fluctuation imaging, ltSOFI). ltSOFI has the potential to obtain super-resolution images by taking advantage of fluorescence lifetime blinking under wide-field lifetime detection. The proof-of-concept for ltSOFI was demonstrated through numerical simulation of high-order cumulant analysis on fluorescence lifetime blinking emitters. As a tentative experimental demonstration, we obtained super-resolution lifetime imaging from time-lapse FLIM recording of HeLa cells expressing a cAMP sensor using ltSOFI method. ltSOFI is expected to initiate a new dimension in the lifetime domain for blinking-based super-resolution microscopy. LAY DESCRIPTION: We report on a promising super-resolution imaging scheme in fluorescence lifetime domain (lifetime super-resolution optical fluctuation imaging, ltSOFI). ltSOFI has the potential to obtain super-resolution images by taking advantage of fluorescence lifetime blinking under wide-field lifetime detection. Past advances in super-resolution fluorescence microscopy primarily rely on the spatiotemporal modulation of the fluorescence intensity. Although the applications of the Q-dot blinking have been discussed in the literature, most of the discussions have focused on the blinking of fluorescence intensity. Few studies have shown the possibility of super-resolution imaging through fluorescence lifetime fluctuations. In this paper, we proposed the ltSOFI scheme that explored the possibility of super-resolution reconstruction from the blinking of fluorescence lifetime. The proof-of-concept for ltSOFI was demonstrated through numerical simulation of high-order cumulant analysis on fluorescence lifetime blinking emitters. As a tentative experimental demonstration, we obtained super-resolution lifetime imaging from time-lapse FLIM recording of HeLa cells expressing a cAMP sensor using ltSOFI method. The ltSOFI method is expected to initiate a new dimension in the lifetime domain for blinking-based super-resolution microscopy. Moreover, the existing fluorescence lifetime imaging microscopy and super-resolution nanoscopy can benefit from the implementation of ltSOFI to significantly improve the imaging spatial resolution of fluorescence lifetime images. In addition, the proof-of-concept demonstration achieved by the numerical simulation and tentative experiment will provide a new perspective for obtaining fluorescence lifetime images with much finer details.

In fluctuation-based optical nanoscopy, investigating high-density labeled subcellular structures with high fidelity has been a significant challenge. In this study, based on super-resolution radial fluctuation (SRRF) microscopy, the joint tagging (JT) strategy is employed to enable fast high-density nanoscopic imaging and tracking. In fixed cell experiment, multiple types of quantum dots with distinguishable fluorescence spectra are jointly tagged to subcellular microtubules. In each spectral channel, the decrease in labeling density guarantees the high-fidelity super-resolution reconstruction using SRRF microscopy. Subsequently, the combination of all spectral channels achieves high-density super-resolution imaging of subcellular microtubules with a resolution of ~62 nm using JT assisted SRRF technique. In the live-cell experiment, 3-channel JT is utilized to track the dynamic motions of high-density toxin-induced lipid clusters for 1 minute, achieving the simultaneous tracking of many individual toxin-induced lipid clusters spatially distributed significantly below the optical diffraction limit in living cells.

In recent years, metal clusters-based photoelectrocatalysis has elicited considerable attention; nonetheless, the exploitations of high efficiency metal clusters–semiconductor heterostructured photoelectrodes are still in the infant stage. Herein, by judiciously capitalizing on glutathione-capped gold (Aux) nanoclusters and graphene quantum dots (GQDs) as building blocks and spatially hierarchically ordered nanoporous TiO2 nanotube arrays (NP-TNTAs) as a conceptual semiconductor platform, GQDs and Aux clusters were rationally and closely integrated on the framework of NP-TNTAs through a progressive electrostatic self-assembly strategy. It was unraveled that Aux clusters play a decisive role in triggering the cascade interfacial charge transfer from GQDs to NP-TNTAs owing to their cooperative synergy, thereby affording conspicuously enhanced solar-powered photoelectrochemical (PEC) water splitting performances under simulated solar light irradiation. Furthermore, the specific PEC water splitting mechanism was unambiguously determined, which for the first time bridges the gap between metal clusters and carbon materials in terms of intrinsic correlations in the charge transfer pathway. It is anticipated that our work would spur further interest in exploring metal cluster-based PEC systems for solar energy conversion. MOE (Min. of Education, S’pore)

Three-dimensional imaging cannot be achieved easily using previously developed localization super-resolution techniques. Here, we present a three-dimensional multimodal sub-diffraction imaging technique with spinning-disk (SD) confocal microscopy called 3D-MUSIC, which not only has all the advantages of SD confocal microscopy, such as fast imaging speed, high signal-to-noise ratio, and optical-sectioning capability, but also extends its spatial resolution limit along all three dimensions. Both axial and lateral resolution can be improved simultaneously by virtue of the blinking/fluctuating nature of modified fluorescent probes, exemplified with the quantum dots. Further, super-resolution images with dual modality can be obtained through super-resolution optical fluctuation imaging (SOFI) and bleaching/blinking-assisted localization microscopy (BaLM). Therefore, fast super-resolution imaging can be achieved with SD-SOFI by capturing only 100 frames while SD-BaLM yields high-resolution imaging.

Motion control system is the core component of high density packaging equipment, the characteristics of its movement performance directly determines the performance and quality of the high density packaging equipment. Based on this, this paper presents a method to enhance the dynamic performance and setting performance of motion control system by means of fine tuning for the movement parameters of the movement system, A high performance motion control card is developed for real-time control and real-time data processing on the multi-axis control platform in our experiments. In addition, the high efficient real-time analytical software is developed and applied to the experiments. The interface of the software real-time displays the movement characteristic curve of movements. The experimental results show that in the case of other conditions unchanged, fine tuning for the movement parameters of the motion system brings benefits of lower undershoot and faster settling of motions. Experimental results show that the performance and quality of the high density packaging equipment is greatly improved through the optimization of the motion control parameters of the Multi-Axis Motion Control System.

Large normal material dispersion acts as an obstacle in the generation of visible optical frequency combs (OFCs) in microcavities. The trajectory separation of light propagation aggravates the dispersion unbalance in the visible region. Dispersion engineering devoted to compressing the separation reaches a bottleneck due to manufacturing difficulties. In this article, we demonstrated that the separation of the light trajectory can be used to manipulate the cavity dispersion. In a bilayer concentric spherical microcavity (CSM), the visible anomalous dispersion was achieved numerically by precisely matching the separated trajectory with the appropriate materials. Furthermore, we simulated the generation of an optical soliton in the visible region based on the proposed microcavity. Our work provides a clue for the visible dispersion control, and the proposed BK7/silica CSM will be an interesting platform for the visible OFC generation.

The large normal dispersion of the fundamental mode (TEn=1 mode) in the whispering gallery modes (WGM) microsphere is detrimental to the visible comb generation. Herein, we demonstrate that this fundamental limitation can be removed by considering the high-order radial modes (TEn=2 mode) of the hybrid microsphere cavity (HMC). The studied HMC consists of a high-refractive-index coating (TiO2 or HfO2) and silica microsphere. The simulated electric field energy distribution and measured Q value in our experiment show that optical confinement of the coating effectively excites the TEn=2 mode and reduces the free spectral range (FSR) and modal dispersion. In addition, the observed redshift of WGM and decreased trend of FSR are in accordance with simulations. The zero-dispersion wavelength can be linearly shifted to a shorter wavelength or even into the visible region with the reduction of coating thickness or refractive index and larger microcavity, which advances the visible comb generation.

Advances in light-sheet microscopy have enabled the fast three-dimensional (3D) imaging of live cells and bulk specimens with low photodamage and phototoxicity. Combining light-sheet illumination with super-resolution imaging is expected to resolve subcellular structures. Actually, such kind of super-resolution light-sheet microscopy was recently demonstrated using a single-molecule localization algorithm. However, the imaging depth and temporal resolution of this method are limited owing to the requirements of precise single molecule localization and reconstruction. In this work, we present two-photon super-resolution light-sheet imaging via stochastic optical fluctuation imaging (2PLS-SOFI), which acquires high spatiotemporal resolution and excellent optical sectioning ability. 2PLS-SOFI is based on non-linear excitation of fluctuation/blinking probes using our recently developed fast two-photon three-axis digital scanned light-sheet microscope (2P3A-DSLM), which enables both deep penetration and thin sheet of light. Overall, 2PLS-SOFI demonstrates up to 3-fold spatial resolution enhancement compared with conventional two-photon light-sheet (2PLS) microscopy and about 40-fold temporal resolution enhancement compared with individual molecule localization-selective plane illumination microscopy (IML-SPIM). Therefore, 2PLS-SOFI is promising for 3D long-term, deep-tissue imaging with high spatiotemporal resolution.

The gap between slab and self-compacting concrete is one of the typical disease for CRTSIII slab ballastless track structure under service condition. This paper established finite element mechanical analysis model of track structure including rail, fastener, track slab, portal steel, self-compacting concrete, isolation layer and base according to the CRTSIII track slab structure characteristics, an "t" type reinforcement scheme of portal steel was proposed, and analyses the vertical stress characteristics of the interface between slab and self-compacting concrete under train and temperature gradient load before and after reinforce portal steel. The results show that when the interface appears gap and is non-gap, the vertical maximum tensile stress of interface is respectively reduced 80% and 87% after reinforce portal steel. It can also reduce the probability of the occurrence of gap between the slab and self compacting concrete, slow down the expansion rate of the isolated region, and improve the durability of rail structure in the course of service. Keywords-CRTSIII Type Slab Ballastless Track Structures; Temperature Gradient; Gap between Slab and SelfCompacting Concrete; Reinforce Pportal Steel; Interfacial Stress

Research purposes: In recent years, according to on-site observation, it is found that CWR in ballastless track will produce lateral deformation in sporadic bending form. For high speed railway, it is easy to stimulate hunting motion of locomotive and rolling stock and has a great im pact on driving stability, comfort and safety. Through carrying on monitoring experiment on late ral deformation of rail on ballastless track, the time- dependent property of lateral deformation of rail will be obtained, which attaches great significance to revealing the mechanism of lateral deformation of rail and ensuring the stability of the ballastless track lines, as well as safety and comfort of driving. In troduction Our country applies a large number of high-speed railway CWR in Ballastless track. The fastening system of ballastless track is directly connected with the concrete bed, compared with the ballast tra ck, the stability of ballastless track is better and has enough vertical and horizontal resistance, which is generally considered to be away from track buckling accidents and not to check its stability (1-6). And the ballastless track stability theory at home and abroad is short of systematic research (7). But under special foundation conditions, such as the transition section between bridge and tunnel, due to be comprehensively affected by the train random loading, initial irregularity of rail and lateral expansion of bridge or other factors, the geometry state of the track changes relatively fr equently, which plays a crucial role on the safety of the whole line and the quality of its ope ration.In August 2007, China Academy of Railway Sciences surveyed geometry state of the track(gauge and track alignment) of Jialing River Bridge, the Jiangjia bridge and Mu Yukou tunnel on the Suiyu line, three abnormal geometry state of the track was measured in the mouth of the tunnel and transition between road and bridge with the rail irregularity of the gauge deviation of 2.0~2.5mm and sporadic bending wavelength of 4m(8,9). Study on basic characteristics and va riation rules of track geometry state at transition section with scientific and comprehensive e valuation of track geometry state attach great scientific research value and engineering significance to revealing the sporadic bending phenomenon and the guidance of track maintenance for ba llastless track CWR in high-speed railway.

An experiment that study on the dynamic characteristics of CRTS III slab track structure on roadbed under high-speed train load was carried out. The full-scale test model of CRTS III slab track structure had been established based on track-roadbed dynamic model test system. Test results show that after train load 7.2 million times, the stiffness of isolation layer increased by 1 time, while the performance of other parts of the track structure had little change. According to the CRTSIII slab track structure characteristics, an finite element mechanical analysis model of track structure was established, which include rail, track slab, door type steel, self-compaction concrete and base. Taking load action 0 million times, 200 million times, 400 million times and 600 million times for example, the displacement and stress of track structure could be calculated. Results show that test values and theoretical values are in good agreement.

This paper established mechanical analysis model of track structure including rail, track slab, door type tendon, self-compacting concrete and base according to the CRTSIII track slab structure characteristics, and analyzed the force condition between interface of track slab and selfcompacting concrete under different loads. After a series of laboratory testing, obtained the bonding strength between track slab and self-compacting concrete, ranged from 0.736MPa to 1.76MPa, and analyzed the cause of the gap of slab edge, gap of slab center, gap under rail by compared it with the theoretical calculation value. Results show that the negative temperature gradient loads is the main cause leading to the gap of slab edge and the corner of slab is most vulnerable while the train loads and the positive temperature gradient loads are the main causes of the gap of slab center and gap under rail, and the position of 1.0m away from the longitudinal of slab center and the edge of end-slab under the rail are most likely to get gap. KeywordsCRTSIII Slab Ballastless Track; Interface; Gap; Cause Analysis

The interface bond damage between the slab and self-compaction concrete is one of the most common damages of CRTSIII slab track. According to the CRTSIII slab track structure characteristics, an finite element mechanical analysis model of track structure was established, which include rail, track slab, door type steel, self-compaction concrete and base. Furthermore, the influence of interface bond damage on the mechanical properties of CRTSIII slab track was analyzed. Results show that compared with interface in good condition, the stress of track structure increased with the increase of the length of interface bond damage. Among them, the range of interface vertical stress, track slab and self-compaction concrete stress remarkable increased. Under train load, the maximum increase range of track structure stress was up to 9 times compared with interface in good condition. Under temperature gradient load, the maximum increase range of track structure stress was up to 2.4 times compared with interface in good condition. Under train and temperature gradient coupling loads, the maximum increase range of track structure stress was up to 11 times compared with interface in good condition.

Super-resolution optical fluctuation imaging (SOFI) is a fast and low-cost live-cell optical nanoscopy for extracting subdiffraction information from the statistics of fluorescence intensity fluctuation. As SOFI is based on the fluctuation statistics, rather than the detection of single molecules, it poses unique requirements for imaging detectors, which still lack a systematic evaluation. Here, we analyze the influences of pixel sizes, frame rates, noise levels, and different gains in SOFI with simulations and experimental tests. Our analysis shows that the smaller pixel size and faster readout speed of scientific-grade complementary metal oxide semiconductor (sCMOS) enables SOFI to achieve high spatiotemporal resolution with a large field-of-view, which is especially beneficial for live-cell super-resolution imaging. Overall, as the performance of SOFI is relatively insensitive to the signal-to-noise ratio (SNR), the gain in pixel size and readout speed exceeds the loss in SNR, indicating sCMOS is superior to electron multiplying charge coupled device in context to SOFI in many cases. Super-resolution imaging of cellular microtubule structures with high-order SOFI is experimentally demonstrated at large field-of-view, taking advantage of the large pixel number and fast frame rate of sCMOS cameras.

Based on multicolor quantum dots (QDs) labeling, the joint tagging assisted super‐resolution radial fluctuation (JT‐SRRF) nanoscopy achieves high‐fidelity super‐resolution imaging of subcellular microtubules and fast live‐cell parallel tracking of cholera toxin subunit B (CTB) induced lipid clusters spatially distributed below the optical diffraction limit. This method paves the way for fast high‐density parallel tracking, which is especially beneficial for the investigation of the intensive dynamics in live‐cell applications. Further details can be found in the article by Zhiping Zeng, Jing Ma, Peng Xi, and Canhua Xu ( e201800020 ).

In this study, in situ experiments were conducted to study the changing characteristics of the lateral and longitudinal resistance of a ballast bed, and a three-dimensional model for the ballast bed and sleeper was constructed based on the discrete-element method. The effects of the lateral and longitudinal resistance of the ballast bed, such as gravel ballast grading, sleeper depth, the angle of the shoulder slope, and ballast bed shoulder width, among others, were studied. The results suggest that (1) the lateral and longitudinal resistance of the ballast bed increases with the widening of ballast grading, and within the size distribution limits, the resistance of the ballast bed satisfies the specification; (2) the lateral and longitudinal resistance of ballast bed increases with an increase in the sleeper depth and the resistance of ballast bed satisfies the specifications for sleeper depth greater than 150 mm; (3) the lateral resistance of the ballast bed increases with a decrease in the angle of the shoulder slope, whereas the longitudinal resistance remains unchanged and the resistance of the ballast bed satisfies the specifications for slope gradient of 1:1.75 or less; and finally, (4) the lateral resistance of the ballast bed increases with the widening of the ballast bed shoulder, whereas the longitudinal resistance remains unchanged, and the resistance of ballast bed satisfies the specifications when the shoulder width is greater than 400 mm.

The self-organized nanograting manufactured by irradiating the transparent materials with the femtosecond laser has aroused wide interests in photonic applications in recent years. Although the mechanism of nanograting formatting has not yet been fully understood, the essential property of the optical birefringence can be precisely acquired by controlling the energy fluence of the femtosecond laser. In this paper, we proposed a novel application of the self-organized nanograting in a division-of-focal-plane polarimeter. Based on the rigid-coupled-wave algorithm, the optical characteristics of the nanograting and the polarimeter were comprehensively analyzed and discussed.